Automated Phasor Segmentation of Fluorescence Lifetime Imaging Data for Discriminating Pigments and Binders Used in Artworks
Year: 2022
Authors: Mattana S.; Dal Fovo A.; Lagarto J.L.; Bossuto M.C.; Shcheslavskiy V.; Fontana R.; Cicchi R.
Autors Affiliation: National Institute of Optics–National Research Council (CNR-INO), Largo E. Fermi 6, Florence, 50125, National Institute of Optics–National Research Council (CNR-INO), Largo E. Fermi 6, 50125, Florence, Italy;, , , Italy; National Institute of Optics–National Research Council (CNR-INO), Largo E. Fermi 6, Florence, 50125, National Institute of Optics–National Research Council (CNR-INO), Largo E. Fermi 6, 50125, Florence, Italy;, , , Italy; Biophotonics Platform, Champalimaud Clinical Centre, Champalimaud Foundation, Av. Brasilia, Lisbon, 1400-038, Biophotonics Platform, Champalimaud Clinical Centre, Champalimaud Foundation, Av. Brasilia, 1400-038, Lisbon, Portugal, , , Portugal; Biophotonics Platform, Champalimaud Clinical Centre, Champalimaud Foundation, Av. Brasilia, Lisbon, 1400-038, Biophotonics Platform, Champalimaud Clinical Centre, Champalimaud Foundation, Av. Brasilia, 1400-038, Lisbon, Portugal, , , Portugal; Department of Physics, University of Florence, Via G. Sansone 1, Sesto Fiorentino, 50019, Department of Physics, University of Florence, Via G. Sansone 1, 50019, Sesto Fiorentino, Italy;, , Italy; Becker & Hickl GmbH, Nunsdorfer Ring 7-9, Berlin, 12277, Becker & Hickl GmbH, Nunsdorfer Ring 7-9, 12277, Berlin, Germany;, , Germany; Privolzhskiy Research Medical University, Nizhny Novgorod, 603005, Privolzhskiy Research Medical University, 603005, Nizhny Novgorod, Russia, , Russian Federation; European Laboratory for Non-Linear Spectroscopy (LENS), Via Nello Carrara 1, Sesto Fiorentino, 50019, European Laboratory for Non-Linear Spectroscopy (LENS), Via Nello Carrara 1, 50019, Sesto Fiorentino, Italy, , Italy
Abstract: The non-invasive analysis of fluorescence from binders and pigments employed in mixtures in artworks is a major challenge in cultural heritage science due to the broad overlapping emission of different fluorescent species causing difficulties in the data interpretation. To improve the specificity of fluorescence measurements, we went beyond steady-state fluorescence measurements by resolving the fluorescence decay dynamics of the emitting species through time-resolved fluorescence imaging (TRFI). In particular, we acquired the fluorescence decay features of different pigments and binders using a portable and compact fibre-based imaging setup. Fluorescence time-resolved data were analysed using the phasor method followed by a Gaussian mixture model (GMM) to automatically identify the populations of fluorescent species within the fluorescence decay maps. Our results demonstrate that this approach allows distinguishing different binders when mixed with the same pigment as well as discriminating different pigments dispersed in a common binder. The results obtained could establish a framework for the analysis of a broader range of pigments and binders to be then extended to several other materials used in art production. The obtained results, together with the compactness and portability of the instrument, pave the way for future in situ applications of the technology on paintings.
Journal/Review: MOLECULES
Volume: 27 (5) Pages from: 1475-1 to: 1475-11
KeyWords: time-resolved fluorescence imaging, fluorescence lifetime imaging, TCSPC, phasor analysis, Gaussian mixture model, binders, cultural heritageDOI: 10.3390/molecules27051475